Pro Tips For Buying a Backpacking Sleeping Bag

By Michael Lanza

Finding a sleeping bag that’s right for you may be the most confusing gear-buying task. Getting the right one is critical to sleeping comfortably in the backcountry—and in an emergency, your bag could save your life. But with the myriad choices out there, how do you tell them apart, beyond temperature rating and price? This article will explain how to evaluate the key differences between bags to make your choice much more simple.

I’ve slept in many, many bags of all types over a quarter-century of testing gear—formerly as the lead gear reviewer for Backpacker magazine for about 10 years and now even longer for this blog. I’ve zipped inside bags in all seasons, in temperatures from ridiculously warm to -30° F. (Ridiculously warm is more tolerable.)

In this article, I’ll share what I’ve learned about picking out a sleeping bag that will be ideal for your body and your adventures.

I’d love to read what you think of my tips or any of your own. Please share them in the comments section at the bottom of this story. I try to respond to all comments.


Hi, I’m Michael Lanza, creator of The Big Outside, which has made several top outdoors blog lists. Click here to sign up for my FREE email newsletter. Join The Big Outside to get full access to all of my blog’s stories. Click here to learn how I can help you plan your next trip. Please follow my adventures on Facebook, Twitter, Instagram, and Youtube.


General Tips For Buying a Sleeping Bag

•    Know your own body. Do you get cold easily or are you a furnace? Women tend to get cold more easily, and this is a simple function of physics: Women often have a higher ratio of body surface area to mass compared to men, so their bodies lose heat more readily. Those women are more comfortable in a bag made for women, which is shaped differently than a men’s bag and typically has extra insulation in areas like the feet.
•    If you get cold easily, get a bag rated 20 to 25 degrees colder than the coldest temperatures you plan to sleep outside in.
•    People who don’t get cold easily will be more comfortable in a bag rated to within 10 to 15 degrees of the coldest temperatures you plan to sleep outside in—and possibly even a bag rated right around the coldest temp you’ll encounter, provided you have extra clothing to put on, just in case. (I’ve spent many nights around freezing perfectly warm enough in a bag rated 32° F.) Being too hot is no more comfortable than being too cold, and having a bag much warmer than needed means you’re carrying superfluous weight and bulk. (See my tips on lightening your pack weight.)

See my “10 Pro Tips for Staying Warm in a Sleeping Bag.”

Feathered Friends Hummingbird UL 30 sleeping bag.
The ultralight and warm Feathered Friends Hummingbird UL 30 sleeping bag, with 950+-fill down. Click photo to read the review.

Down Vs. Synthetic Bags

Down has traditionally been lighter, more packable, and warmer than many synthetic insulations; but once wet, synthetics still kept you fairly warm, while down feathers become all but useless at retaining heat. Today, the lines between down and synthetic have been blurred somewhat with the development of high-quality, lightweight and compact synthetic insulations like PrimaLoft, and water-resistant down, which retains its ability to trap heat even when wet. 

Down is more packable and very durable, so it still holds an advantage as the insulation of choice if you don’t expect to get that bag wet; and water-resistant down enhances your bag’s performance in common circumstances where it may get damp, such as when condensation builds up inside a tent. Still, even water-resistant down, once saturated, loses much of its ability to keep you warm, and drying out any bag is extremely difficult, if not impossible, in prolonged, wet weather. Synthetic insulation remains the best choice for extended trips in wet environments.

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High-quality down (rated from 800- to 900-fill or higher) is the warmest, lightest, most packable insulation out there, but expensive, while lower-quality down (usually 600-fill) still has the advantages of down, and makes a bag less expensive but also heavier and bulkier. Manufacturers use lower-grade synthetic insulation in bags priced cheaply, making them much heavier and bulkier than better synthetic and down bags—typically too heavy and bulky for backpacking (unless you’re on a very limited budget and don’t mind carrying a big pack).

So the down vs. synthetic choice still comes down to pocketbook issues and the likelihood of your bag actually getting wet.

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See all of my reviews of sleeping bags and air mattresses and sleeping pads that I like at The Big Outside.

 

Tell me what you think.

I spent a lot of time writing this story, so if you enjoyed it, please consider giving it a share using one of the buttons at right, and leave a comment or question at the bottom of this story. I’d really appreciate it.

 

See also my related stories:

5 Tips For Finding the Right Backpack

5 Tips For Spending Less on Backpacking and Hiking Gear

5 Tips For How to Buy a Backpacking Tent

A Practical Guide to Lightweight and Ultralight Backpacking

Ask Me: How Do We Begin Lightening Up Our Backpacking Gear?

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Review: Osprey Talon 22 and Tempest 20 Daypacks

Ask Me: Where Should Our Family Backpack in the Grand Canyon?

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11 thoughts on “Pro Tips For Buying a Backpacking Sleeping Bag”

  1. Good morning Michael. I hope you don’t mind all the questions, but you are the most knowledgeable person I’ve found on outdoor gear and I want the best source I have for answering these questions. I’m reading through all of your sleeping bag reviews and I’m confused on which one I want.

    I’m 5 foot 11 and weigh 160 lbs. and I get cold easily. The places I will be backpacking over the next few years are the Ozarks, Smokies, and Southern Appalachian mountains mainly in spring and fall. The temps are mild here compared to western mountain ranges but still can get pretty cold at night during those times of the year.

    I’m also trying to be as Ultralight as possible with my gear. I’m confused on which sleeping bag can handle 30 degree nights on low end but also not make me burn up if the temps are in the 70’s at night because as you know in the south the weather can swing either way dramatically from day to day. Any thoughts on a bag that might be perfect for me for these conditions?

    Thanks again so much!

    Slade

    Reply
    • Hi Slade,

      Yes, it can be hard to sort through all the sleeping bag choices out there. The above article should help you narrow your preferences, but I’ll offer some suggestions.

      I’d go for a 30-degree bag because a warmer bag will feel like too much on those nights in the 40s, 50s, and warmer. But if you get cold easily AND frequently backpack on nights in the 40s and 30s—and that question should be a primary driver of your decision—then get a 20-degree bag.

      For maximum warmth per ounce of bag, high-quality down—800-fill or higher—is unquestionably the way to go. It costs more but I always consider the cost per night or mile of use I’ll put on gear. Plus, the high-end bags are often stuffed with more insulation and built better than less-expensive models. You’ll probably get your money’s worth out of a good bag.

      My top recommendation for you is the Feathered Friends Hummingbird 30 or 20. Another good one, though not quite as warm (though similarly rated), is the Therm-a-Rest Hyperion 32. For a 20-degree down bag, the Sierra Designs Nitro 800 is a good one.

      You can support my work on my blog by purchasing through any of the affiliate links to online retailers in those reviews.

      Good luck.

      Reply
      • Thanks Michael! I really appreciate you taking the time to answer my questions. You have helped me more already than I ever imagined when subscribing to The Big Outside. I’m very grateful.
        Thanks,
        Slade

        Reply
  2. Hi Michael,
    I am like you in that I don’t get cold easily. For summer backpacking trips I have generally used a 30 degree bag, such as a Marmot bag. I also have a Mountain Hardware Phantom 32, but it does not seem as warm; and also I prefer a full length zipper. In general I bring a 30 degree bag and also may bring a bag liner if I might need extra warmth (such as a mid to late September trip in the Canadian Rockies). I am curious what specific sleeping bag you use in your summer hiking trips, e.g., a hike in the Sierras in August or early September?

    Reply
    • Hi Jeff,

      Thanks for asking. I don’t get cold too easily, but I also find that I can wear a couple of base layers, long underwear, socks and a hat in my bag to supplement its warmth when needed (and I’m often wearing the socks and hat, even if just in a T-shirt and underwear). You might find my “10 Pro Tips for Staying Warm in a Sleeping Bag” useful.

      I’m often testing a new bag on my trips (to review), but like you, I generally take an ultralight, 30-degree, down bag on summer trips in mountain ranges like the High Sierra and throughout the West, including the Canadian Rockies (where I have plans to backpack this summer, crisis-permitting). I have used Hardwear’s Phantom and found it adequately warm for September in the Sierra, and various Marmot bags, which are usually plenty warm.

      Some bags I’ve liked and reviewed recently include the Therm-a-Rest Hyperion 32, the REI Magma series, and the more-affordable, synthetic Nemo Kyan/Azura series.

      I hope that’s helpful. I’ll certainly be testing and reviewing more bags this summer. Thanks for the comment.

      Reply
      • Yes I do very much the same – I wear a couple of wool base layers, long underwear, socks and a toque hat in my bag to supplement its warmth. This has the added benefit of when I get up in the middle f the night to “use the facilities” it is not such a huge temperature shock. I also bing a silk bag liner.

        I am looking at the Feathered Friends Flicker UL Wide sleeping bag / quilt, which looks very interesting to me.I am not sure how I will fare without a sleeping bag hood, but often times I wear my down jacket to bed, and for my head I can wear a buff, a toque (warm beanie) over the buff and can also put on my warm jacket hood as well. The other option is the Feathered Friends Swift UL 30 degree bag, which is more of a traditional sleeping bag. If you have any wisdom to share on these I would love to hear it.

        Thanks for the answer!

        Reply
        • Hey Jeff,

          I haven’t used either of the Feathered Friends bags you mentioned, but I am a fan of Feathered Friends products in general. (See this menu of my FF reviews.) They make great bags that tend to be among the warmest bags in any temperature rating category.

          I have not embraced quilts because I shift in my sleep. I generally like a bag with a hood, though a hat often suffices in the temps in which I’d use a 30-degree bag; if I’m pushing that bag’s temp rating, though, I’d like to have the hood.

          I hope that’s helpful.

          Reply
  3. Hi Michael,

    Have you tried any of the ultralight quilts from smaller companies (Katabatic Gear, Nunatak, etc.)? They seem like a great alternative to three-season bags, especially for side and stomach sleepers who don’t usually use a hood. It’s a bit difficult to find reviews of them though, as they aren’t as widely used as mummy bags. I was just wondering if you’ve had any positive or negative experiences with them

    Thanks!

    Reply
  4. I think a full-length zipper is most-useful in the summer. It lets you open the bag fully and use it as a quilt instead. You’re right that being too warm is uncomfortable, and it makes you sweat. That moisture is bad no matter what kind of insulation you use.

    That seems to be the problem with getting wet. I’m knocking on wood as I type this, but I’ve never completely soaked my gear while fording a creek or capsizing a boat. It’s condensation and possibly sweat that are going to wet your bag, I think.

    I’m starting to experiment with carrying a lighter and less warm bag than most people would suggest, and making up the difference by sleeping in a down hoodie jacket and down booties. (Feathered Friends makes down socks with a removable boot shell.) You only use the bag when you’re sleeping, but the jacket and boots are useful in camp (stargazing for example) and sometimes when you stop on the trail. So I feel like this is probably a good way to split up the weight. But I need more trips to test this idea.

    Reply
    • Good points, Forrest. I agree about the full-length zipper being most useful in mild temperatures. I’ve rarely gotten my sleeping bag very wet, partly because I will use a waterproof dry bag-style stuff sack whenever I’m on a water-based trip or backpacking in a situation where I could get very wet. I like the Sea to Summit eVent Compression Dry Sacks for that: http://www.seatosummit.com/products/display/1.

      But in general, the more common reason a bag gets wet is from condensation, either on the interior tent walls or directly on your bag (from body heat), which occurs in colder temps, i.e., just above or below freezing. If it’s below freezing, you can conveniently knock the frost or ice off your bag first thing in the morning. If the condensation isn’t frozen, you can wipe surface dampness off the bag’s shell. But on prolonged, below-freezing trips, condensation can collect inside the bag’s insulation, so it becomes important to dry the bag in warm sunshine whenever possible. A synthetic bag is obviously better if the insulation gets damp, but they’re very bulky. The new types of water-resistant down bags are a good choice for long, cold trips.

      I also prefer to take as light a bag as I know I can get away with using on a trip, given the anticipated coldest temps, and using my extra clothes for added warmth as needed.

      Reply

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